US4557676A - Hydrostatic control device, particularly steering device - Google Patents

Hydrostatic control device, particularly steering device Download PDF

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Publication number
US4557676A
US4557676A US06/550,256 US55025683A US4557676A US 4557676 A US4557676 A US 4557676A US 55025683 A US55025683 A US 55025683A US 4557676 A US4557676 A US 4557676A
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US
United States
Prior art keywords
housing
directional valve
casing
valve
throttle gap
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US06/550,256
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English (en)
Inventor
Hans C. Petersen
Erik Kyster
Svend E. Thomsen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DAFOSS A Co OF DENMARK AS
Danfoss AS
Original Assignee
Danfoss AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Danfoss AS filed Critical Danfoss AS
Priority to US06/756,659 priority Critical patent/US4575321A/en
Assigned to DAFOSS A/S, A COMPANY OF DENMARK reassignment DAFOSS A/S, A COMPANY OF DENMARK ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KYSTER, ERIK, PETERSEN, HANS C., THOMSEN, SVEND E.
Application granted granted Critical
Publication of US4557676A publication Critical patent/US4557676A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
    • B62D5/09—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by means for actuating valves
    • B62D5/093—Telemotor driven by steering wheel movement
    • B62D5/097—Telemotor driven by steering wheel movement gerotor type
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86574—Supply and exhaust
    • Y10T137/86638—Rotary valve

Definitions

  • the invention relates to a hydrostatic control device, particularly steering device, comprising a metering motor and a flat slide directional valve which, in response to actuation of a control shaft and rotation of the metering motor, assumes a neutral position or one of two operating positions in which pressure fluid passes through an operating motor and the metering motor in series, at least the valve element having the primarily moved slide surface being mounted for rotation between the other slide surface and a wall parallel thereto.
  • valve plates and a gear of the metering motor surrounded by a gear ring are arranged between two end walls of an outer housing.
  • the first valve plate is fixed to turn with a control shaft. Together with the second valve plate it forms a flat slide directional valve. Together with the gear ring, the second valve plate forms a distributing valve.
  • the directional valve which is normally in its neutral position is brought to one of two operating positions by turning the control shaft, so that pressure fluid is led through the metering motor to a steering operating motor.
  • the metering motor causes the second valve plate to follow the first valve plate.
  • Both valve plates comprise through going apertures so that openings are provided on both sides for entering or leaving pressure fluid.
  • control devices of this kind are well suited for steering heavy and slow vehicles and corresponding applications because they amplify the actuating force of the operator. If, however, faster vehicles are to be steered in this way or similar controls are to be carried out, difficulties are encountered, most frequently an over control.
  • a radial piston machine is also known (DE-AS No. 25 44 849) which has a multi-way distributing valve, wherein blind bores provided in a rotatable annular plate connect control orifices, which lie on a circle and are connected to the radial cylinders to control orifices which are disposed therebetween and are connected alternately to the supply side and the discharge side.
  • a high pressure zone in the form of an annular groove adjoins a first throttle gap which extends up to the periphery of the annular plate.
  • the opposite side of the annular plate which is thus connected thereto serves as an intermediate pressure zone.
  • the latter is associated with a second throttle gap which leads to the low pressure side and is disposed in the same plane as the first throttle gap but changes in the opposite sense upon axial displacement of the annular plate. In this way, one achieves a balancing of pressures which prevents abutment of the relatively rotatable parts.
  • the invention is based on the problem of providing a hydrostatic control device of the aforementioned kind in which over control can be avoided.
  • a steering device built up in this manner is also to be suitable for faster vehicles.
  • valve element comprises, on that side where openings are provided for the supply and withdrawal of pressure fluid, a high pressure zone with an associated first throttle gap and on the opposite side an intermediate pressure zone which is connected to the first throttle gap and is connected to the low pressure zone by way of an associated second throttle gap which changes oppositely to the first throttle gap.
  • the valve element envelops the metering motor and has openings for the supply and withdrawal of pressure fluid only on one side.
  • the valve element and metering motor By unifying the valve element and metering motor, all control orifices are disposed on one side and separating forces will later also act on the valve element on only one side. Consequently, the intermediate pressure zone on the opposite side suffices to avoid friction.
  • valve element has orifices on both sides for the supply and withdrawal of pressure fluid and provision is made on both sides for a high pressure zone and an intermediate pressure zone each with an associated first and second throttle gap, which are interconnected to form two separate systems.
  • Such conventional valve elements in known control devices can be axially loaded from the one side or the other by reason of the throughgoing apertures. For this reason, two systems are provided each preventing deflection to a respective side.
  • Such double pressure balancing is suitable not only for hydrostatic control devices with metering motors but quite generally for control devices having a flat slide valve of which the valve element having the one slide surface is rotatably mounted between the other slide surface and a wall parallel thereto.
  • valve element it is advisable for the valve element to have on both sides a respective annular groove as the high pressure zone and an annular groove as the intermediate pressure zone, adjacent to which there is an outlet opening forming an annular rim.
  • the outlet opening adjacent to the respective high pressure zone is connected to the intermediate pressure zone of the other side and the outlet opening adjacent to the intermediate pressure zone is connected to the low pressure side. In this way, sufficient space remains for accommodating the control orifices necessary for the valve function.
  • the high pressure zone is formed by an annular groove, the adjacent outlet opening by a central bore and the intermediate pressure zone and the adjacent outlet opening by outer annular grooves.
  • the central bore takes up little space.
  • valve element in a further development, it is advantageous for the valve element to have on both sides annular grooves acting as high pressure zones but of different diameter, the intermediate pressure zone on the one side being a central depression and on the other side an annular groove, the passages extending from the outlet openings being substantially parallel.
  • This arrangement may not be symmetrical on both sides but permits better adaptation to the control orifices necessary for the valve function.
  • the axial play of the valve element prefferably be so small that in the neutral position the control orifices of the flat slide on the low pressure side are sealed from the other control orifices even in the absence of pressure in the high pressure and intermediate pressure zones.
  • a seal will suffice such that the operating motor and/or metering motor lose no liquid to any marked extent.
  • the axial play can be about 5-50 micrometers, preferably about 10 micrometers.
  • the at least one high pressure zone is connected by way of a respective check valve that opens towards it to the pump connection and each of the two operating motor connections. This ensures that, in special cases, when the pump does not deliver the highest pressure, the respectively highest pressure for the pressure balancing is effective, i.e. pressure balancing is possible even under unfavourable conditions.
  • FIG. 1 is a longitudinal section through a first embodiment of the invention
  • FIG. 2 is a section on the line II--II in FIG. 1;
  • FIG. 3 is a section on the line III--III in FIG. 1;
  • FIG. 4 is a longitudinal section through a second embodiment of the invention.
  • FIG. 5 is a diagrammatic section through a modified valve element
  • FIG. 6 is a section on the line VI--VI in FIG. 5.
  • an outer housing 1 comprises an end wall 2, a sleeve 3, a valve plate 4, a passageplate 5, a passage plate 6 an intermediate plate 7 and a connecting plate 8, held together by tension screws 9.
  • the connection plate 8 comprises five connections of which a pump connection 10, a container connection 11 and an operating motor connection 12 are visible.
  • a second operating motor connection and a connection which is selectively connectible to an additional operating circuit or to the container are disposed beyond the plane of the drawing.
  • a metering motor 13 comprises an internally toothed gear ring 14 and an externally toothed gear 15 which define compression chambers 16 between each other.
  • the gear 15 is connected by a cardan shaft 17 to a control shaft 18 which can be provided with a hand control wheel.
  • the control shaft 18 is supported at the outer housing 1 by way of an axial bearing 19.
  • the gear 15 turns and planetates in relation to the gear ring 14.
  • the latter together with an end wall 20, a distributing valve plate 21, an intermediate plate 22 and a slide valve plate 23, defines a motor housing 24 which is held together by screws 25.
  • the plates 21 to 23 may be permanently interconnected.
  • the slide plate 23 covers the screw holes.
  • the container connection 11 is connected to an opening 27 near the end wall 2 by way of an outlet passage 26 formed by bores in the metering motor 13 and the other parts of the machine.
  • a depression 29 in plates 22 and 23 is also part of the outlet passage.
  • an arrangement 30 is inserted in the depression. This arrangement comprises rotation limiting means in the form of two supporting bars 31 and 32 which are pushed into extensions 33 of the depressions corresponding to the corners of a rectangle. Therebetween are neutral position springs 34 and 35 in the form of two curved leaf springs.
  • a distributing valve 36 is formed between the distributing valve plate 21 and the side of the gear 15.
  • a flat slide directional valve 37 is formed between the two plates 23 and 4.
  • the slide surface 39 has three circumferentially successive sets of control orifices, namely a container control orifice 40 connected to the container T by way of the outlet passage 26 and the container connection 11, a metering motor control orifice 41 connected to a connection K1 of the metering motor 13, a pump control orifice 42 a neutral position control orifice 43 in the form of a radial slot, and a further pump control orifice 44, which are connected to one another, as well as a metering motor control orifice 45 connected to the connection K2 of the metering motor.
  • a container control orifice 40 connected to the container T by way of the outlet passage 26 and the container connection 11
  • a metering motor control orifice 41 connected to a connection K1 of the metering motor 13
  • a pump control orifice 42 a neutral position control orifice 43 in the form of a radial slot
  • a further pump control orifice 44 which are connected to one another, as well as a metering motor
  • the slide surface 38 contains an operating motor control orifice 46 connected by way of the one operating motor connection 12 to the connection S1 of the operating motor bringing about the control movement, a pump control orifice 47 connected to the pump P by way of the pump connection 10, a neutral position control orifice 48 in the form of a radial slot which has adjoining throttle depressions and connected by way of a connection (not shown) to the container or a subsequent operating circuit, a further pump control orifice 49 and an operating motor control orifice 50 connected to the operating motor.
  • These control orifices are likewise repeated cyclically.
  • the pump connection 10 communicates with the neutral position control orifices 43, 48 by way of the control orifices 47, 42 and 49, i.e. "open Centring" operation will take place.
  • the metering motor control orifices 41 and 45 as well as the operating motor control orifices 46 and 50 are closed. If the control shaft 18 is turned clockwise, the gear 15 follows and, since the compression chambers 16 are closed, so does the gear ring 14. Consequently, the slide surface 39 turns relatively to the slide surface 38.
  • the connection by way of the neutral position control orifices 43, 48 is now gradually throttled.
  • the pump control orifice 47 comes into communication with the metering motor control orifice 41 and the metering motor control orifice 45 comes into communication with the operating motor control orifice 50.
  • the operating motor control orifice 46 comes into registry with the container control orifice 40. Pressure fluid therefore flows over the metering motor to the operating motor and back to the container. The amount compressed in the metering motor corresponds accurately to the angle of rotation of the control shaft so that the operating motor is adjusted precisely proportionally to the control shaft rotation. Converse conditions apply for rotation in the anticlockwise direction.
  • a high pressure zone 51 is formed by an annular groove in the slide surface 39 of motor housing 24, because this annular groove will be at pump pressure by way of the neutral position control orifices 43.
  • the subsequent marginal zone 52 together with the slide surface 38 of the outer housing 1, forms a first throttle gap 53 which opens into an annular gap 54 between the motor housing 24 and sleeve 3.
  • an intermediate pressure zone 57 is formed between the end surface 55 of the outer housing 1 and the end surface 56 of motor housing 24, the intermediate pressure zone being bounded at the radially inner circumference by a second throttle gap 58 which leads to the opening 27 of the outlet passage 26.
  • the outer housing 101 comprises an end chamber 102, a sleeve memver 103 and a connecting plate 108. These parts are interconnected by beading the ends of the sleeve 103 over.
  • the connecting plate 108 carries several connections on the outside, for example a pump connection 110, leading to a pump P, a container connection 111, leading to the container T, and two operating motor connections 112 and 112a leading to the connections S1 and S2 of an operating motor 159.
  • the inner side forms a slide surface 138 of a flat slide directional valve 137. Different passages 160 in the interior of the connecting member establish communication between the connections and the control orifices in the slide surface 138.
  • a control shaft 118 is fixed to an end wall 120 of a metering motor 113.
  • the end wall 120 is connected by screws 125 to a gear ring 114 of the metering motor and to a distributing plate 121.
  • These parts turning with the control shaft 118 are supported against a step of the outer housing 101 by way of an axial bearing 119.
  • a gear 115 forming compression chambers 116 together with the gear ring 114 is connected by a cardan shaft 117 to a valve element 123 of which the slide surface 139 together with the slide surface 138 of the directional valve 137 and its opposite slide surface 161 together with the adjoining surface of the distributing plate 121 form a distributing valve 136.
  • In the depression 129 there is an arrangement which comprises the rotation limiting means and the neutral position springs.
  • the valve element 123 comprises orifices 162 which may contain pressure fluid.
  • the opposite side 161 has orifices 163 to which the same applies.
  • a high pressure zone 151 consisting of two annular grooves and outlet openings 164 therebetween are provided in the surface 139 so that first throttle gaps 153 are formed therebetween.
  • Bores 165 parallel to the axis lead to an intermediate pressure zone 157 formed as an annular groove on the opposite side 161, adjoining which there is an outlet opening 166 in the form of an annular groove communicating with the container T.
  • Second throttle gap 158 is therefore formed in the adjacent area.
  • This system is opposite a separate system comprising a high pressure zone 151a in the form of two annular grooves on the side 161 with interposed outlet openings 164a to produce the first throttle gap 153a. Bores 165a parallel to the axis lead to the intermediate pressure zone 157a in the form of a compression. Next to it there is an outlet opening 166a which again communicates with the container T to result in the second thorttle gap 158a.
  • This combination of high pressure and intermediate pressure zones ensures that the valve element 123 will substantially maintain its accurate position irrespective of whether the operating fluid exerts a load to the left or to the right. Displacement of the valve element 123 to the left leads to an increase in the throttle gap 153 in the one system and to a reduction in the throttle gap 158. Consequently, the intermediate pressure rises in zone 157. Simultaneously, there is a reduction in the throttle gap 153a in the other system and an increase in the throttle gap 158a. Consequently, the intermediate pressure rises in the zone 157a. Both effects occur in unison to return the valve element 123 substantially to its neutral position.
  • valve element 123 seeks to move to the right, the throttle gaps 153a and 158 are increased and the throttle gaps 153 and 158a are reduced. Consequently, the intermediate pressure in the zone 157a rises whilst that in zone 157 drops. Accordingly, the valve element 123 is returned to the neutral position.
  • control shaft 118 If the control shaft 118 is turned during operation, not only the gear ring 114 is turned with it, but also the gear ring 115 because of the pressure fluid enclosed in the compression chambers 116 and this rotary movement is transmitted to the valve element 123. It is adjusted relatively to the slide surface 138. Since no friction occurs because of the pressure balancing, a comparatively small torque will suffice.
  • a conduit 167 leading to the high pressure zones is connected by way of a first check valve 168 to the pump connection 110 by way of a second check valve 169 to the operating motor connection 112 and by way of a third check valve 170 to the operating motor connection 112a. If, therefore, the operating motor 159 is loaded by external forces, and a pressure obtains in the one conduit leading to the operating motor that is higher than the pump pressure, this maximum pressure automatically reaches the high pressure zones so that sufficient forces are available for preventing displacement of the valve element 123.
  • valve element 223 Each of both sides 239 and 261 of valve element 223 comprise a high pressure zone 251 and 251a formed by a respective annular groove connected by a conduit 267 to the pump P. Outlet openings in the form of central bores 264 and 264a are connected by way of oblique passages 265 and 165a to intermediate pressure zones 257 and 257a which are disposed on the opposite sides and in the form of annular grooves. Inwardly, thereof, there are annular grooves 266 and 266a connected to the container T by way of a conduit 271. Consequently, each side is formed with first throttle gaps 253 and 253a and second throttle gaps 258 and 258a. Space for the control orifices which are not illustrated is provided between the annular grooves 251 and 266. The function of this valve element is similar to that of the FIG. 4 example.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Servomotors (AREA)
  • Multiple-Way Valves (AREA)
US06/550,256 1982-11-24 1983-11-10 Hydrostatic control device, particularly steering device Expired - Fee Related US4557676A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US06/756,659 US4575321A (en) 1983-11-10 1985-07-19 Hydrostatic control device, particularly steering device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3243402A DE3243402C2 (de) 1982-11-24 1982-11-24 Hydrostatische Steuereinrichtung, insbesondere Lenkeinrichtung
DE3243402 1982-11-24

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US06/756,659 Division US4575321A (en) 1983-11-10 1985-07-19 Hydrostatic control device, particularly steering device

Publications (1)

Publication Number Publication Date
US4557676A true US4557676A (en) 1985-12-10

Family

ID=6178882

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/550,256 Expired - Fee Related US4557676A (en) 1982-11-24 1983-11-10 Hydrostatic control device, particularly steering device

Country Status (6)

Country Link
US (1) US4557676A (enrdf_load_stackoverflow)
JP (1) JPS59140170A (enrdf_load_stackoverflow)
BR (1) BR8306449A (enrdf_load_stackoverflow)
CA (1) CA1224381A (enrdf_load_stackoverflow)
DE (1) DE3243402C2 (enrdf_load_stackoverflow)
DK (1) DK155102C (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4631010A (en) * 1982-11-24 1986-12-23 Danfoss A/S Hydrostatic control device, particulary steering device
US5404722A (en) * 1993-01-29 1995-04-11 Eaton Corporation Torque generator with reduced backlash
US6598553B1 (en) * 2002-02-13 2003-07-29 Mark X Steering Systems, Llc Power assist marine steering system
US20090211412A1 (en) * 2005-07-13 2009-08-27 Stryker Trauma Gmbh Screwdriver for an Inner Profile Screw

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4342933C2 (de) * 1993-12-16 1995-10-19 Danfoss As Vorrichtung zum Steuern des einer hydrostatischen Lenkeinheit zuzuführenden Drucks

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3597128A (en) * 1969-04-10 1971-08-03 Trw Inc Hydraulic device having hydraulically balanced commutation
US3658448A (en) * 1970-11-27 1972-04-25 George V Woodling Rotary and axially compressible valve system means
US4232708A (en) * 1979-06-25 1980-11-11 Trw Inc. Fluid controller
US4411607A (en) * 1980-04-23 1983-10-25 G. L. Rexroth Gmbh Internal gear machine with rotary pressure balanced valve disc
US4439119A (en) * 1979-08-13 1984-03-27 Danfoss A/S Gerotor machine with commutating valving through the ring gear

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1528997A1 (de) * 1965-03-05 1970-05-14 Danfoss As Drehkolbenmaschine
DE1653822C3 (de) * 1967-12-14 1974-02-28 Danfoss A/S, Norburg (Daenemark) Hydrostatische Steuereinrichtung
CH584374A5 (enrdf_load_stackoverflow) * 1974-12-12 1977-01-31 Cyphelly Ivan J

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3597128A (en) * 1969-04-10 1971-08-03 Trw Inc Hydraulic device having hydraulically balanced commutation
US3658448A (en) * 1970-11-27 1972-04-25 George V Woodling Rotary and axially compressible valve system means
US4232708A (en) * 1979-06-25 1980-11-11 Trw Inc. Fluid controller
US4439119A (en) * 1979-08-13 1984-03-27 Danfoss A/S Gerotor machine with commutating valving through the ring gear
US4411607A (en) * 1980-04-23 1983-10-25 G. L. Rexroth Gmbh Internal gear machine with rotary pressure balanced valve disc

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4631010A (en) * 1982-11-24 1986-12-23 Danfoss A/S Hydrostatic control device, particulary steering device
US5404722A (en) * 1993-01-29 1995-04-11 Eaton Corporation Torque generator with reduced backlash
US6598553B1 (en) * 2002-02-13 2003-07-29 Mark X Steering Systems, Llc Power assist marine steering system
US20090211412A1 (en) * 2005-07-13 2009-08-27 Stryker Trauma Gmbh Screwdriver for an Inner Profile Screw
US8347768B2 (en) 2005-07-13 2013-01-08 Stryker Trauma Gmbh Screwdriver for an inner profile screw
US8770068B2 (en) 2005-07-13 2014-07-08 Stryker Trauma Gmbh Screwdriver for an inner profile screw

Also Published As

Publication number Publication date
DK530783A (da) 1984-06-28
JPS59140170A (ja) 1984-08-11
CA1224381A (en) 1987-07-21
BR8306449A (pt) 1984-06-26
DK155102B (da) 1989-02-06
DK530783D0 (da) 1983-11-21
DE3243402A1 (de) 1984-05-24
JPH0347230B2 (enrdf_load_stackoverflow) 1991-07-18
DE3243402C2 (de) 1986-10-09
DK155102C (da) 1989-06-26

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AS Assignment

Owner name: DAFOSS A/S, NORDBORG, DENMARK, A COMPANY OF DENMAR

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:PETERSEN, HANS C.;KYSTER, ERIK;THOMSEN, SVEND E.;REEL/FRAME:004450/0940

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Effective date: 19971210

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362